Lawyers for the government and American Telephone & Telegraph Co. yesterday told a federal jury they will not be ready for trial of the Justice Department's landmark antitrust suit against AT&T if pretrial procedures continue at their current pace.

Although U.S. District Judge Harold Greene did not delay the scheduled Oct. 27 opening of the trial of the six-year-old case, he did delay from Aug. 25 until Sept. 15 the completion date of stipulations or issues in the case. Lawyers are to appear again before Greene during the week of Aug. 25 to give another status report.

But Gerald Connell, the lead attorney in the case for the Justice Department, told Greene that the government needed two months to prepare for trial once the stipulations were agreed to. Connell said the 21 lawyers on the case for the government are handling both the stipulation negotiations and the trial itself.

In fact, negotiations have begun on only about half of the pages of grounds in the case, Connell said, although he and George Saunders, the lead attorney for AT&T, agreed that both sides have been working diligently on the stipulation talks. "We are actually killing ourselves, and the government is too," Saunders said.

Connell said the government expected to call about 100 witnesses during about 75 trial days, while Saunders said AT&T would call from 100 to 150 witnesses in a presentation of 60 to 90 days.

"If it appears that really substantial progress is being made, then I'll consider extending the trial date," Greene said. "I'm very reluctant to do that."